This specification relates to providing digital content items (e.g., advertisements and/or other types of content) to users in a display environment. Examples of display environments include electronic publications such as webpages accessible via a web browser application executing on a computer system that has connectivity with the Internet, on a point-of-sale kiosk or, more generally, on any appropriate display in essentially any suitable context or environment.
Publishers (e.g., web site publishers) may include content such as content sponsoring in their respective publications to help financially support their operations. Some publishers do not maintain a content sponsoring (e.g., advertising) infrastructure, and thus depend on third party content sponsor serving companies to recruit content sponsors and to serve content items to the publishers' sites. Third party content sponsor serving companies can, depending on various factors, control which content items are displayed to which users and under what circumstances. For example, a content sponsor serving company can provide directed content items, such as advertisements, to certain groups of users.